DETOXIFICATION OF METALS--IN VITRO AND IN VIVO STUDIES

金属解毒——体外和体内研究

• 批准号: 6217645
• 负责人: H VASKEN APOSHIAN
• 金额: $ 12.65万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6217645
• 关键词: SDS polyacrylamide gel electrophoresis; affinity chromatography; animal tissue; arsenic; autoradiography; biotransformation; detoxification; environmental contamination; environmental toxicology; erythrocytes; gas chromatography; glutathione; human tissue; laboratory mouse; laboratory rabbit; metal metabolism; metalloproteins; methylation; methyltransferase; protein purification; reduction; toxicant interaction; waste disposal; waste treatment

Description: Arsenic and other toxic metals and metalloids are known to have been dumped at numerous superfund sites. Two important biological mechanisms for detoxifying metal ions are protein binding, and methylating them via enzymes such as methyl transferases which use S- adenosylmethionine and/or vitamin B12 as coenzymes. This appears to be true for arsenic, selenium and possibly lead. The molecular mechanisms by which methylations are accomplished are unknown. The enzyme reactions for the biotransformation of arsenate/arsenite are unknown. Enzyme reactions for the biotransformation of arsenate/arsenite to the less toxic methylarsonate and much less toxic dimethylarsinate have been studied only to a limited extent using crude, impure enzyme homogenates of bacteria, fungi or the rat. There have also been limited, in vivo, metabolic studies in experimental animals and humans in which arsenic compounds were given and the metabolites in the urine identified. This project deals with the isolation and purification of human enzymes and binding proteins that detoxify arsenate/arsenite in order to study the molecular mechanisms of these detoxifications. In this way, for the first time, the enzymatic mechanisms for the detoxification of arsenate/arsenite in humans will be understood. Once the arsenic biotransforming enzymes have been characterized, other metal ions such as lead, selenium, cadmium, as well as, halogenated aromatic hydrocarbons will be studied to see if they inhibit the enzymatic biotransformation of arsenic. The control and regulation of these purified enzymes will be studied and inhibitors and stimulators of the enzymes will be studied. Urine of animals challenged with arsenate will be tested for methyltransferase activities to determine whether these enzymes can be used as biological indicators of the body's concentration of toxicologically active forms of arsenic. A challenge test for arsenic in humans using DMPS (2,3- dimercaptopropane-1-sulfonic acid) will be developed. Such a challenge test will be helpful for determining the exposure of humans to arsenic and will be useful to determine arsenic exposure of humans near superfund sites.

描述：已知砷和其他有毒金属和类金属 已经被扔在无数的超级基金网站上。两个重要的生物学 解毒金属离子的机制是蛋白质结合，以及 通过使用S的甲基转移酶等酶将它们甲基化- 腺苷蛋氨酸和/或维生素B12作为辅酶。这看起来像是 对于砷、硒，可能还有铅，情况都是如此。分子机制 目前尚不清楚甲基化是通过什么方式完成的。酶反应 对于亚砷酸盐/亚砷酸盐的生物转化尚不清楚。酶 亚砷酸盐/亚砷酸盐生物转化反应的研究 有毒的甲基砷酸盐和毒性小得多的二甲基砷酸盐 仅在有限范围内使用粗制、不纯的酶匀浆进行研究 细菌、真菌或老鼠。在体内，也有有限的， 砷在实验动物和人类中的代谢研究 给予化合物，并鉴定尿液中的代谢物。这 该项目涉及人体酶的分离和纯化以及 解毒砷酸盐/亚砷酸盐的结合蛋白以研究 这些解毒的分子机制。这样一来，对于 首次提出了黄曲霉毒素解毒的酶机制 人体内的亚砷酸盐/亚砷酸盐将会被理解。一旦砷 生物转化酶已被表征，其他金属离子如 如铅、硒、镉以及卤代芳香族 将对碳氢化合物进行研究，看看它们是否会抑制酶 砷的生物转化。对这些的控制和管制 纯化的酶将被研究，并抑制和刺激 将对酶进行研究。挑战砷盐意志的动物的尿液 进行甲基转移酶活性测试，以确定这些 酶可以作为人体浓度的生物指示器 毒理活性形式的砷。对…的挑战测试 使用DMPS(2，3-二醇丙烷-1-磺酸)测定人体中的砷 将会被开发出来。这样的挑战测试将有助于 确定人类对砷的暴露情况，将有助于 确定超级基金地点附近人类的砷暴露水平。